In recent years, with the widespread use of computers, ink jet printers have come into wide use for performing printing on paper, film, cloth, or the like not only in offices, but also at home.
The ink jet recording method is accomplished by the following system: a system in which droplets are ejected through the application of pressure by a piezoelectric element; a system in which droplets are ejected by thermally forming bubbles in an ink; an ultrasonic system; or a system in which droplets are attracted and ejected by an electrostatic force. As the ink compositions for such ink jet recording, water-based inks, oil-based inks, or solid (molten type) inks are used. Out of these inks, the water-based inks are mainstream in terms of production, handling property, odor, safety, and the like.
The colorants to be used for these inks for ink jet recording are required to have a high solubility in solvents, to be capable of high density recording, to be good in hue, to be excellent in fastnesses to light, heat, air, water, and chemicals, to be less likely to spread on an image-receiving material because of its good fixability thereon, to be excellent in storage stability as an ink, to have no toxicity, to have high purity, and further to be available at low cost. However, it is very difficult to seek colorants satisfying these requirements at high level.
Various dyes and pigments have already been proposed for use in ink jet, and have come into actual use. However, in actuality, colorants satisfying all the requirements have not yet been found. As for such conventionally well known dyes and pigments as those given color index (C. I.) numbers, it is difficult to make compatible the hue and the fastness required of the ink for ink jet recording. The study has been so far pursued on fast dyes having favorable hues, and the development of colorants excellent as colorants for ink jet has been pursued.
Yellow dyes for ink jet heretofore widely known are direct azo dyes, acid azo dyes, and the like.
C. I. Acid Yellow Nos. 17, 23, and 26 as the acid azo dyes, and C. I. Direct Yellow Nos. 86, 120, and 132, and the like as the direct azo dyes are used for ink jet yellow ink (e.g., JP-A-55-150396 and JP-A-2001-240781).
Further, the dyes more excellent in fastness than these dyes are also used as ink jet yellow inks (e.g., JP-A-2001-279145)
On the other hand, it has been shown that there are the following problems. Many of dyes are slightly water soluble, and tend to precipitate. Accordingly, such extraordinary printed portion as the portion in which the dye aggregates on a high-density printed portion (bronzed portion; the defective portion which has changed in film quality into mat form as compared to the normal printed portion) is formed upon printing, resulting in a deterioration in image quality. In particular, bronzing tends to occur at a multicolor mixed portion.